Method of making light metal alloys



Patented Oct. 20, 1925.

UNITED STATES PATENT- OFFIE,

LLIAM B. VEAZEY, OF CLEVELAND, OHIO, AND EDWARD C. BURDICK, F MIDLAND, MIGHIGAN, ASSIG'NORS '1O THE DOW CHEMICAL COMPANY, OF MIDLAND, MICHI- GAN, A CORPORATION OF MICHIGAN.

METHOD OF MAKING LIGE'I REF-TAIL ALLOYS.

Ito Drawing.

To all whom it may concern:

lBe it known that we, WILLIAM R. VEAZEY and EDWARD G. BURDICK, both'citizens of the United States, and residents of Cleveit land, county of Cuyahoga, and State of @hio, and of Midland, county of Midland, and State of Michigan, respectively, have jointly invented a new and useful Improvement in Methods of Making Light Metal Alloys, of which the following is a specifica tion, the principle of the invention being herein explained and the best mode in which we have contemplated applying that'principle, so as to distinguish it' from other inventions.

Aside from the difficulties inherent in the handling ofmolten magnesium, such difliculties being well set forth in U. S. Patent No. 906,820 to Racowicz, dated December 15, till 1908, special difiiculties are encountered when it is sought to alloy with the magnesium one or more additional metals in relatively small amount. Particularly when it is attempted to add to such magnesium as an alloylng ingredient either copper or any other metal which has a specific gravity higher than and a melting point much above that of magnesium, the direct addition of the alloying metal in solid form to molten magnesium, as described for example in German Patent No. 122312 to Aluminiumund- Magnesium Fabrik, dated December 16, 1900, results in the former sinking promptly to the bottom of the mass of magnesium, or where the latter is floated, as described in the patent just cited, ina bath of suit able flux material then such heavier metal will drop entirely through the molten magnesium and into the flux below the latter. llf it is sought to overcome this difficulty by heating the magnesium high enough for the copper to alloy quickly, there is considerabl danger of burning the magnesium, and even illlil where the copper, or other metal, is cut up into very fine pieces to facilitate the alloying operation at a lower temperature, considerable time is consumed in the alloying process.

@ne object of the present invention, ac-

cordingly, is to provide a simple and expeditious method for adding alloying metals to a larger mass of magnesium, whereby the thorough inter-mixture of the ingredients is insured and particularly the retention of Application filed November at, 1921. Serial No. 51?,95.-

' all of the alloying ingredient. A" further object is to avoid the necessity of employing temperatures so high as to endanger the magnesium taking fire.

To the accomplishment of the foregoing and related ends the invention, then, consists of the steps hereinafter fully described .while heavier than such metal, will have proper surface tension to promptly and etfectively coat the metal. As an example of such a flux, approximately equal parts of anhydrous magnesium chloride and sodium chloride may be employed, and-if the specific gravity of such flux. proves inadequate to float the metal after it has been alloyed, a

small amount of barium chloride may be w added.

A small amount of the molten magnesium metal is then taken up ii a ladle, the film of flux covering the surface of the latter in the pot being brushed aside for this pun pose and all or a art of the alloying metal, depending upon tie total percentage of the latter to be added to the batch, is placed in such ladle and melted with the magnesium therein, whereby an alloy relatively rich. in such added metal is produced. The contents of the ladle are then gradually added to the main body of molten magnesium with the result that the added ingredient will diffuse throughout the mass and; not drop through into the body of flux on which the latter floats and so be lost.

As soon as the introduction of the preliminary alloy thus made in the ladle has been efi'ected, the whole mass is well puddled and the operation may then he regarded as complete and the molten alloy cast either into ingots or directly into the form of mechanical parts, such as pistons or the like, for which it is intended to .be used.

Alloys in which magnesium is the predominant constituent, i. e., alloys containing per cent or more of this metal, maybe readily made in accordance with the forewill tively small amount of each additional metal may then be .separately introduced in the same fashion aswas the added ingredient that goes to make such binary alloy;-or, on

, the other hand, two or more of such additional ingredients may be at once admixed with the relatively small amount of the molten magnesium taken up in a ladle as before and so form a preliminary alloy relatively high in such added ingredients, which alloy is subsequently added to the 'main body of the molten. magnesium metal, re-' sulting in the production of the desired alloy in which such magnesium is the predominant ingredient.

Where an alloy of the class described is desired in which, in addition to aluminum, cop er or other metal of similar relatively hig melting point is to be included as an ingredient, we have found it advanta eous to first alloy such copper with the alummum so as to give an alloycontaining approximately equalparts of each metal. The melting point of such resulting alloy will be below that of magnesium, and when it is added to a little magnesium in the ladle, the ternary combination is efiected without difiiculty. The resultant ternary alloy is then intermixed with the main body of the magnesium and where the amount of aluminum required in making such preliminary aluminumcopper alloy is less than the total amount of aluminum to be added, the remaining quantity of this metal is then s'eparatelyintroduced into the main body of metal in the pot, preferably being first melted along with a little magnesium in a ladle, as before described. In the same way, where an alloy of more complex formula is tobe made, and.

still other ingredients as, for example, zinc.

and cadmium, are to be added, thesewill be introduced in the same fashion, being admixed with a relatively small amount of molten magnesium apart from the main body thereof,-either singly or together, and then added to such main body.

It Wlll thus be seen that our improved method is adaptable for the making of light metal alloys in which magnesium is the predominant ingredient, irrespective of whether one or more additional ingredients are employed. In other words, a simple binary alloy of magnesium with either aluminum,

tin, zinc, cadmium, or the like, may be thus .made, or ternary and higher, more complex alloys. By means of our im roved method .we, furthermore, are success 1 in eliminating all of the practical difiicu lties heretofore encountered in handling magnesium al-- loys, and the resultant alloy in the molten condition in which it exists in the pot after the alloying process proper has been completed, may be directly employed in the casting either of ingots or mechanical parts by simply ladling such molten metal into suit able molds. 1

Other modes of applying the principle of our invention may be employed instead of the one explained, change beingmade as regards the method herein disclosed, provided the step or steps'stated by any of the following claims or the equivalent of such stated step or steps be employed.

We therefore particularly point out and vdistinctly claim as our invention alloy to the remaining quantity oi magmesium in molten state.

2. In a method of making a light metal alloy in which magnesium largely predominates, the steps which consist in melting a measured quantity of magnesium, floating same in a bath of flux, interfusing the proper amount of the alloying metal with a relativelysmall quantity of such molten magnesium, and then adding the resulting alloy to the remainder of such magnesium.

3. In a method of making alight metal alloy in 1 which magnesium largely predominates, the steps which consist in melting a measured quantity of magnesium floating same in a bath of flux consisting of a mixture of magnesium chloride and an alkali metal chloride, interfusing the proper amount of the alloying metal with a relatively small quantity of such molten magnesium, and then adding the resulting allpy to the remainder of such magnesium.

4. In a method of making a. light metal alloy in which magnesium largely predomi nates, the steps which consist in melting a measuredequantity of magnesium, floating same in abath of flux consisting of a mixture of magnesium and sodium chlorides in approximately equal proportions, interfusing the proper amount of the alloying metal with a relatively small quantity of such molten magnesium, and then adding the resulting alloy to the remainder of such magnesium.

5. In a method of making a light metal alloy in which magnesium largely predominates, such alloy also including aluminum and another metal, the steps which consist in first making an alloy of the aluminum and such other metal, interfusing such aluminum alloy with a relatively small quantity of magnesium, and then adding the resultretaoee ing alloy to the remaining quantity of magnesium in molten state.

' *3. In a method of making a light metal alloy in which magnesium largely predominates, such alloy also including aluminum and copper, the steps which consist in first making an alloy of the aluminum and copper, interfusing such aluminum-copper alloy with a relativelysmall quantity of magnesium, and then adding the resulting alloy to the remaining quantity of magnesium in molten state. 7. In a method of making a light metal alloyin which magnesium largely predominates, such alloy also including aluminum and copper, the steps which consist in first making an alloy of the aluminum and copper in approximately equal proportions, interfusing such aluminum-copper alloy with a relatively small quantity of magnesium, then adding the resulting alloy to the remaining quantity of magnesium in molten state, and similarly interfusing with a relatively small amount otmagnesium and adding to the main body of the latter any additional aluminum required by the formula.

8. in a method of making a light metal alloy in which magnesium largely predominates, such alloy also including aluminum and copper, the steps which consist in first making an alloy of the aluminum and copper in approximately equal proportions, interfusing such aluminum-copper alloy with a relatively small quantity of magnesium, then adding the resulting alloy to the remaining quantity of magnesiumin molten state, and similarly interfusing with a relatively small amount of magnesium and adding to the main body of the latter any additional constituent required by the formula having a melting point not greatly exceeding that of magnesium.

9. In a method of making a light metal alloy in which magnesium largely predominates, suclr alloy also including aluminum and copper, the steps which consist in first making an alloy of thealuminum and copper in approximately equal proportions, interl'using such aluminum-copper alloy with a relatively small quantity of magnesium, then.

adding the resulting alloy to the remaining quantity of magnesium in molten state, and

similarly interfusing with a relatively small amount of magnesium and adding to the main body of the latter any additional alua portion of such magnesium apart from the main body of the latter, and then returning such portion with alloying metal interfused therewith to such main body.

11. lln a method of making a light metal alloy in which magnesium largely predominates, the steps which consist in .meltin a measured quantity of magnesium, floating same in a bath of flux capable of forming a protective coating over the surface of such magnesium, adding the alloying metal in molten state to a portion of such magnesium apart from the main body of the latter, andthen returning. such portion with alloying metal interfused therewith to such main body.

12. In a method of making a light metal alloy in which magnesium largely predominates, the steps which consist in melting a measured quantity of magnesium, floating same in a-ba'th of flux consisting of a mixture of magnesium chloride and an alkali metal chloride, adding the alloying metal to a portionof such magnesium apart from the main body of the latter, and then returning such portion with alloying metal intert'used therewith to such main body.

13. In a method of making a light metal alloy in which magnesium largely predomi nates, the steps which consist in melting a measured quantity of magnesium, floating same ina bath of flux consisting of a mixture of magnesium chloride and an alkali metal chloride, adding the alloying metal in molten state to a portion of such magnesium apartfrom the main body of the latter, and then returning such portion with alloying metal inter-fused therewith to such main body.

Signed by me this 21st day of November, 1921.

lVllLLlAM R. VEAZEY. Signed by me this 23 day of November, 1921.!

EDWARD C. BURDICK. 

